The Tunisian Olympic Committee (French: Comité National Olympique Tunisien, CNOT) sent the nation's largest delegation to the Games, surpassing the number of athletes sent to Beijing by almost two thirds. A total of 83 athletes, 63 men and 20 women, competed in 17 sports. Men's basketball, men's handball, and men's indoor volleyball were the only team-based sports in which Tunisia was represented at these Olympic games. There was only a single competitor in artistic gymnastics, sailing, shooting, and taekwondo.

Notable Tunisian athletes included freestyle swimmer and defending champion Oussama Mellouli, who competed at his fourth Olympics, tennis player and former Youth Olympic games participant Ons Jabeur, and fencing sisters Azza and Sarra Besbes. Heykel Megannem, captain of Tunisia's handball team, made his Olympic comeback in London after a twelve-year absence and was the nation's flag bearer at the opening ceremony.

Tunisia left London with three medals, which were all awarded to the team in athletics and swimming. This was the nation's most successful Olympics, winning the largest number of medals in its history, sending its largest delegation ever to the games due to the presence of team-based athletes, and making Olympic history for two legendary athletes. Middle-distance runner Habiba Ghribi became the first Tunisian female athlete to win an Olympic medal in the women's steeplechase. Meanwhile, Oussama Mellouli became the first Olympic swimming champion at both pool and open water, and became most successful Tunisian athlete in Olympic history with two gold medals.[2]

Tunisian swimmers have so far achieved qualifying standards in the following events (up to a maximum of 2 swimmers in each event at the Olympic Qualifying Time (OQT), and potentially 1 at the Olympic Selection Time (OST)):[17][18]